(1) Technical Field
The invention pertains to lift-roof covers for use with load beds of light trucks, providing improved access to the load bed and extending functions to other uses, with major focus upon achieving these benefits in a manner best accommodating manufacturing and distribution processes broadly in use relative to conventional fixed mount cab high covers (caps) of the prior art. Applicable US classifications include 296/100.1, 100.6 hinged load covers, 296/165 expansible or collapsible vehicle body, 296/176 expansible/collapsible from a first to a second configuration for camping. The disclosure describes key improvements beyond the concept described by U.S. Pat. No. 5,102,185, these improvements providing simplification in manufacturing processes and improvements in convenience of installation and operation to levels approaching those for conventional fixed mount caps (cab high covers) of the prior art. These improvements also increase the functional reliability of the complete lift-roof cover system and make possible enhanced aesthetic appeal by eliminating obvious appearance differences from conventional fixed mount caps of the prior art which have demonstrated highest user acceptance levels. In particular, objection has been made to separation lines between the forward wall and the lift-roof/cap shell when these are visible in side view. The application to a new use of existing technology for hinging and weather sealing rear hatch assemblies for fixed mount caps of the prior art overcomes this deficiency, while supporting functional and economic benefits associated with use of technology which is familiar to practitioners of the art to which the invention pertains.
(2) Description of Related Art
Through review of the prior art defined in patents relating to pickup truck load bed covers issued subsequent to Lake, U.S. Pat. No. 5,102,185, it can be seen that much effort has been focused on inventing alternate means to provide improved access for loading/unloading and facilitating adaptation to uses beyond cargo protection while also making available a roof height equal to or greater than that of the vehicle cab. Examples include the following:
Ekonen et al, U.S. Pat. No. 5,104,175, and Herndon, U.S. Pat. No. 5,951,095, describe transformable cover assemblies which unfold from a low profile on the load bed to provide full enclosure with a roof level equivalent to that of a cab high, fixed mount cap of the prior art. However, they add complexity while giving up significant degrees of security and integrity of appearance with the vehicle when in the cab high operating mode.
Plamondon, U.S. Pat. No. 6,149,217, Alexa, U.S. Pat. No. 6,000,745, Moberly, U.S. Pat. No. 5,443,295, and Hanning, U.S. Pat. No. 6,471,282, describe retractible flexible covers of cab height which fail to provide the security and integrated (with vehicle) appearance provided by most fixed mount, molded caps.
Aragon et al, U.S. Pat. No. 5,516,182, Herzberg et al, U.S. Pat. No. 5,203,603, and Hutchinson, U.S. Pat. No. 5,655,809, describe telescoping cab high covers having rigid outer paneling. These concepts provide better cargo security, but add significant complexity and also fail to provide the fully integrated appearance provided by most conventional, fixed mount, molded caps.
Fowler, U.S. Pat. No. 6,471,280, describes a cover with hard molded shell but, in order to provide improved loading access, requires removal of the shell, an obvious inconvenience.
Baldwin, U.S. Pat. No. 6,439,647, Dence, U.S. Pat. No. 6,394,532, and Lambden, U.S. Pat. No. 6,007,137, describe cab high rigid covers pivoting from one or both sides in a manner providing increased interior volume as desirable for adaptation to camping or improved side loading access. However they fail to provide improved access from the rear suitable for loading popular wheeled equipment.
Harkins, U.S. Pat. No. 5,209,543, describes an apparatus for enclosures such as pickup bed tops, including a pair of folding top panels longitudinally hinged for closing along the top centerline. In order to achieve the benefits of lift-roof improved access loading from the rear, considerable and costly complexity is added.
Medlin, U.S. Pat. No. 5,595,418, and Enninga, U.S. Pat. No. 5,104,175, describe means for mounting a cap to a load bed in ways accommodating pivotal rotation of the complete camper shell about a forward axis by lifting from the rear. However, significant complexity appears to be added in hardware and processes necessary for installation and acceptable function. Furthermore, sealing at the forward wall to load bed interface is not addressed.
Moore et al., U.S. Pat. No. 5,421,633, describes a camper shell intended for mounting directly to a truck frame on a vehicle assembly line, adaptable to having its roof pivotally raised from the rear and having flexible walls for camping attached and/or removed. Moore et al appears focused on application of lift-roof functional benefits via a high production volume vehicle assembly process requiring high levels of manufacturing tooling investment and does not appear to address needs of manufacturing and distribution systems in place within the conventional cap industry.
The concepts cited above provide various benefits beyond those provided by conventional fixed mount caps of the prior art. In most cases compromises are introduced which are evidently unacceptable to most purchasers of fixed mount, molded caps (historically comprising the primary market for pickup truck covers), who demand an appearance well integrated with styling of the vehicle, together with secure, weatherproof enclosure of the load bed to a height matching that of the vehicle cab. It would appear that Enninga and Medlin are able to retain all key functional and aesthetic benefits provided by conventional caps as long as they are used in the closed condition. When in the open condition cargo space is compromised, due to intrusion of the cap forward wall, which moves rearward as the cap shell is raised and introduces issues with respect to sealing to the load bed forward wall. Also, complexity introduced in the components and associated processes necessary for installation become of particular concern where installation may be completed at multiple locations by individuals with limited experience relative to the product. Therefore, objects of my invention include to provide the benefits of improved access for loading and easy adaptation to alternate uses while minimizing complexity in the installation process and/or costs in added hardware and avoiding compromises relative to benefits already provided by conventional fixed caps of the prior art.
Grise, U.S. Pat. No. 4,452,482, and McGaughey et al, U.S. Pat. No. 4,461,185, describe hatch frame construction for pickup truck caps including an integral hinge for supporting a hatch door in a weatherproof manner with location close to the cap roof edge. These patents are of referent interest in describing adaptation of radius door technology to lift-roof cover application
Ely et al, U.S. Pat. No. 6,179,350, describes a draw latch and various means for providing resistance to keep the members of a latch assembly in a variety of given positions and addresses need for manually raising a catch in order to effect disengagement.
Gromotka, U.S. Pat. No. 5,478,125, describes a draw latch in which rotation of the lever initially disengages the catch and positive contact between the lever and latch arm at a distance from the latch pivot causes the hook arm to kick out. Objects include to provide these functions with parts which are few, durable and reliable in all functions.
P. R. Gley et al, U.S. Pat. No. 3,519,298, describes a positive lock for toggle catch, or draw latch, permitting concomitant release of the catch and movement of the handle to an open position.
The above draw latch patents address need for one-handed convenience in operation. Various methods are described as used in the prior art for positioning handles and latch arms to support convenient operation. Plastic inserts have been employed where corrosion from exposure to the elements could otherwise impair function. Metal-to-metal frictional methods are commonly employed in order to support low cost. However, it would appear that, in practice, most friction or interference methods tend to result in high efforts and/or variation in effort due to wear and/or manufacturing variability. Such methods may be adequate to temporarily retain latch handles to an open position, because full hand strength may be conveniently applied to effect release. However, the control effort with respect to a latch arm pivoting from a latch handle needs to be relatively low in order to support convenient operation, which requires moving the latch arm independently of the handle either immediately before moving the handle, or simultaneously with handle operation, but in any case as a fluid one-handed movement. Accordingly it is an object to provide a draw latch which supports convenient positioning of component parts in operation by applying reliable methods to draw latches having other characteristics suited to lift-roof cover application. This may be best achieved with concepts depending on zero resistance beyond that of a free pivot and force of gravity, or otherwise with a more reliable method of providing frictional resistance than generally employed in the prior art.